February saw the highest monthly dollar value of share buyback authorizations ever, $118.32 billion, according to Birinyi Associates. That eclipsed the record of $118.25 billion in the same month of 2013, notes Robert J. Leiphart, a Birinyi analyst. Typically, about 80% of authorizations are filled, he adds.

Some might interpret this as a contrarian and bearish signal, but Leiphart argues...